Growth Potential of Clostridium perfringens from Spores in Acidified Beef, Pork, and Poultry Products during Chilling

Abstract

The ability of Clostridium perfringens to germinate and grow in acidified ground beef as well as in 10 commercially prepared acidified beef, pork, and poultry products was assessed. The pH of ground beef was adjusted with organic vinegar to achieve various pH values between 5.0 and 5.6; the pH of the commercial products ranged from 4.74 to 6.35. Products were inoculated with a three-strain cocktail of C. perfringens spores to achieve ca. 2-log (low) or 4-log (high) inoculum levels, vacuum packaged, and cooled exponentially from 54.4 to 7.2°C for 6, 9, 12, 15, 18, or 21 h to simulate abusive cooling; the U.S. Department of Agriculture, Food Safety and Inspection Service (USDA-FSIS) recommends a cooling time of 6.5 h. Total germinated C. perfringens populations were determined after plating on tryptose-sulfite-cycloserine agar and incubating the plates anaerobically at 37°C for 48 h. In addition, C. perfringens growth from spores was assessed at an isothermal temperature of 44°C. Growth from spores was inhibited in ground beef with a pH of 5.5 or below, even during extended cooling from 54.4 to 7.2°C in 21 h. In ground beef with a pH of 5.6, the growth was >1 log after 18 h of cooling from 54.4 to 7.2°C. However, 15 h of cooling controlled the growth to <1 log, regardless of the inoculum level. In addition, no growth was observed in any product with a pH ranging from 4.74 to 5.17, both during exponential abusive cooling periods of up to 21 h and during storage for 21 h at 44°C. While <1-log growth of C. perfringens from spores was observed in the pH 5.63 product cooled exponentially from 54.4 to 7.2°C in 15 h or less, the pH 6.35 product supported growth, even after 6 h of cooling from 54.4 to 7.2°C. These challenge tests demonstrate that adjustment of ground beef to pH of 5.5 or less and of barbeque products to pH of 5.63 or less inhibits C. perfringens spore germination and outgrowth during extended cooling periods from 54.4 to 7.2°C up to 15 h. Therefore, safe cooling periods for products with homogeneous, lower pHs can be substantially longer.

Occurrence of Clostridium perfringens vegetative cells and spores throughout an industrial production process of black soldier fly larvae (Hermetia illucens)

“…For instance, Valero et al (2020) demonstrated for a cocktail of a related species, C. sporogenes, that spores could not germinate at a pH below 5.0. Mohammad et al (2020) demonstrated that acidification of cooked rice to a pH of 4.2 inhibited growth of C. perfringens, even when the rice was kept at room temperature for 24 h. Indeed, for optimal growth, C. perfringens requires a pH of 6.0 to 7.0 (Juneja et al, 2013;Paredes-Sabja et al, 2008).…”

Bacterial Contaminants of Poultry Meat: Sources, Species, and Dynamics

“…The prevalence of Staphylococcus aureus on poultry meat products has been addressed, although most of the literature has focused on antibiotic resistance and typing of the isolates [ 63 , 64 , 65 ]. Although there are a few reports on the detection of Clostridium perfringens on poultry meat [ 61 ], most of the literature focuses on assessing and modeling its growth on meat after spore germination following the slaughtering process [ 66 , 67 , 68 ]. Lastly, the emergence of Aeromonas from poultry meat products as a vector of human infection has also been reported [ 10 ].…”

Evaluating the Performance of a New Model for Predicting the Growth of Clostridium perfringens in Cooked, Uncured Meat and Poultry Products under Isothermal, Heating, and Dynamically Cooling Conditions

“…The cooling data contain both single‐ and dual‐rate cooling profiles. For most single‐rate cooling profiles, the temperature decreases exponentially from 54.4 to 7.2 °C or 4.4 °C in 6.5, 9, 12, 15, 18, and 21 h (Thippareddi and others ; Zaika ; Juneja and Thippareddi , ; Smith and others ; Smith and Schaffner ; Sánchez‐Plata and others ; Juneja and others , ; Olds and others ; Juneja and Friedman ; Velugoti and others ; Singh and others ; Li and others ; Decker and others ; Juneja and others ; Kennedy and others ; Redondo‐Solano and others ; King and others ). The single‐rate cooling profiles also include 2 linear cooling profiles from 54.4 to 7.2 °C (King and others ) and 5 customized cooling profiles (Olds and others ; Decker and others ).…”